Containers, and more specifically metallic beverage containers, generally contain a neck on an upper portion that is adapted for interconnection to a metallic end closure. The container end closure is formed from a flat sheet of metallic material and generally includes a pull tab or other form of stay on tab (“SOT”). Beverage containers commonly store carbonated beverages, thus, both the container body and the container end closure are required to withhold internal pressures up to 90 psi while under varying temperatures without catastrophic failure or permanent deformation. Further, the container end closure must be manufactured, stacked, shipped, and sent to a filler prior to being seamed onto a container body filled with a carbonated beverage. Thus, the container and end closure must be designed to resist deformation and failure while utilizing thin metallic materials and allowing compact stacking during shipping and manufacturing.
Food and beverage containers with pull tabs or SOTs are generally known. Various SOTs and related features are disclosed, by way of example, in U.S. Pat. No. 7,926,675 to Rieck et al., the entire disclosure of which is hereby incorporated by reference in its entirety. SOTs are generally rotated by a user to push on a tear panel that is fractured from the end closure along a score line. The amount of force needed to fracture the score line may be large in order to prevent inadvertent opening of the end closure. Additionally, known end closures may buckle when under varying temperatures and internal pressure. If an end closure buckles near the score line and opening, then the score line can crack and release the contents of the container. This is called “peak and leak.” Thus, end closures are often designed to withstand buckling, which generally increases the amount of force a user must exert on the tear panel to fracture the score. Further, many current designs have scores created on a flat panel surface. The flat surface causes springback after the opening load is removed and reduces the area of the opening.
Accordingly, there exists a significant need for a beverage container end closure that will resist buckling, peak and leak, and inadvertent opening while still being easy for a user to open the end closure to access the container's contents.
Previous attempts have been made to manufacture container end closures that reduce the force needed to open the end closure by reducing the score residual (i.e., the material below the score line). However, low score residuals can create transportation leakers as well as stress-cracking issues.
Due to the numerous limitations associated with the prior art described above, the following disclosure describes an improved container end closure that is adapted for interconnection to a container body and that employs a score fracture force reduction feature. This novel feature provides an easy-to-open end closure that also prevents leaking during transportation.